The most surefire way to confirm a wormhole’s existence would be to directly prod a black hole and see if it’s hiding a bridge to elsewhere, but humanity may never have that opportunity. Even so, researchers could rule out some of the most obvious scenarios from Earth. If the monster black hole residing in the churning center of the Milky Way, for instance, is more door than dead end, astronomers could tease out the presence of something on the other side. Black hole researchers have tracked the orbits of stars, such as one called S2, circling this galactic drain for years. Should those stars be feeling the tug from distant doppelgängers beyond the black hole, they’d perform a very particular dance for anybody watching, according to a recent calculation.